Statistical Quality Control Tools

The Use of Statistical Quality Control in Yeast Fermentation and Treatment for Ethanol Production

The researcher offers a case study on the use of statistical quality control to the process of yeast fermentation and treatment for the manufacture of the bio-fuel ethanol. The following performance indicators were examined for establishing the important variables of the fermentation and treatment process: milling capacity, loss in distillation, loss in final effluent, indeterminate loss, accident risks, and non-quality costs. Each performance indicator was given a score to represent its impact on the process. The relationship between preset process factors and performance metrics was also investigated. The analysis identified seven variables as being critical: temperature in the fermentation vats, alcoholic concentration in the fermentation vats, brix of the mash, the temperature of the mash, alcoholic concentration in the vats of yeast treatment, viability and infection in the fermentation vats. Control charts were used to monitor the critical variables. Sampling frequencies were determined by examining the previous impacts of each critical variable on the fermentation process. Therefore, 200 daily samples of each variable were used to plot the control charts. The data was divided into four periods, each of them with 50 daily samples in chronological order on which capability analysis was carried out.

Evaluating the Inefficiencies in Ethanol Production

The monitoring of the fermentation and treatment process sought to determine the existing inefficiencies in the production of ethanol. The presented results indicated some variables presented low or moderate variability, namely the temperature on the fermentation vat, brix of the mash, alcoholic concentration in the fermentation vats, the temperature of the mash, and alcoholic concentration in the vats of yeast treatment. Variables that presented high variability were the viability and the infection in the fermentation vats.

Reference

Sagawa, J. K., & Yamada, R. I. (2013). The Application of Statistical Quality Control Tools to

Monitoring Ethanol Process Production. Brazilian Association of Industrial Engineering

Journal, 1-14. Retreived from

http://www.abepro.org.br/biblioteca/enegep2013_tn_sto_178_015_22238.pdf